Effect of harvest maturity stage and seeding rate on alfalfa yield and quality

Abstract

Cultivated alfalfa (Medicago sativa L.) is a highly productive forage crop with great economic potential. Our objectives were to investigate the effects and interactions of environment, harvest maturity stage, seeding rate and cultivars on alfalfa dry matter yield and quality. The field experiment was carried out over 2010-2012 at the Experimental Field of Institute of Field and Vegetable Crops in Novi Sad, at two locations: (I) Cenej, and (II) Rimski Šančevi, which were characterized by a contrasting soil condition. The experimental treatments included two seeding rates of 8 and 16 kg ha-1, three different harvest maturity stages of alfalfa, and four alfalfa cultivars included as a subplot in every treatment. Harvesting alfalfa five times within a year (cutting in the beginning of flowering) in the second and third year of stand life is the most efficient harvest regime that allows full exploitation of cultivar genetic potential and environmental conditions. There was no difference in yields between harvests at early and full flowering stage (15.9 t ha-1). Data related to forage quality components show increase of nutritive value when harvesting alfalfa in earlier maturity stage. Maturity stage in the moment of harvesting significantly affected all quality parameters. The results obtained suggest that in a temperate climate of Southeast Europe there is little justification for planting higher seeding rates of alfalfa varieties under good establishment practices. Increasing seeding rates above 16 kg ha-1 does not provide a long-term boon in alfalfa production.

Lucerka (Medicago sativa L.) je visokoproduktivna krmna biljka velikog ekonomskog potencijala. Cilj rada je bio da se ispita uticaj uslova spoljne sredine, faze košenja, setvene norme i sorte, kao i njihove interakcije, na prinos i kvalitet suve materije lucerke. Poljski ogled je zasnovan na oglednim poljima Instituta za ratarstvo i povrtarstvo u Novom Sadu, na dva lokaliteta: (I) Čenej, i (II) Rimski Šančevi, različitih zemljišnih karakteristika. Tretmani su uključivali dve setvene norme, od 8 i 16 kg ha-1, tri sistema kosidbe i četiri sorte lucerke, tretirane kao podparcele u svakom tretmanu. Kao najbolji sistem kosidbe, u kojem je ostvarena puna eksploatacija i potencijal sorte, bilo je košenje lucerke pet puta godišnje (kosidba u početku cvetanja) u drugoj i trećoj godini života lucerišta. Prinosi ostvareni košenjem na početku i u punom cvetanju se nisu razlikovali (15,9 t ha-1). Podaci o komponentama kvaliteta krme ukazuju na značajno povećanje nutritivne vrednosti pri kosidbi u ranim razvojnim fazama biljaka lucerke. Fenološka faza biljaka u momentu košenja značajno je uticala na sve parametre kvaliteta. Dobijeni rezultati govore da u umerenom klimatu jugoistočne Evrope postoji opravdanje za setvu manje količine semena. Povećanje setvene norme preko 16 kg ha-1 ne obezbeđuje dugoročnu dobit u proizvodnji lucerke.